Are You Confident of the Diagnosis?

Palmoplantar keratodermas (hereby referred to as PPKs) represent a large, varied group of syndromes that are vastly different with respect to symptoms and clinical presentation. Please refer to Table I for syndrome names, synonyms. Images for the syndromes discussed are cited in the Evidence section at the end of the chapter. The acquired PPKs will not be extensively covered in this chapter but should be mentioned. The acquired PPKs are as follows: Keratoderma climactericum, arsenical keratosis, aquagenic PPK, malignancy-associated PPK, malnutrition-associated PPK and drug-induced keratoderma.

Thickening of the epidermis and extensive widening of keratinocyte intercellular spaces, extending from the first suprabasal layer upwards. Loss of keratinocyte-keratinocyte adhesion and desmosomes in the lower suprabasallayers were small and reduced in numbers

Defective lipid secretion of LG lipid contents, ABCA12 protein is restricted to the LGs in the cytoplasm of epidermal keratinocytes and fuses with the cell membrane to secrete the lipid content to the extracellular space of the stratum corneum.

What you should be alert for in the history

Questions regarding age of onset, past medical history, family information (geographic as well as medical history), erythema, involvement and inclusion of the dorsal aspects of hands and feet should be asked and considered during a clinical examination.

Characteristic findings on physical examination

Characteristic findings on physical examination are variable depending on the gene affected as well as the manifestation which varies from person to person. Please refer to the column “Distinguishing PPK features” on the accompanying table for the most common manifestations of each syndrome. PPKs are generally classified in three categories: Focal, Diffuse, and Punctate.

Positive gene defect results should be expected for the disorders with known genetic causation. Outcomes from other forms of testing such as blood work, urinalysis, or x-ray can be found on the “work-up and treatment” column on the accompanying table.

Diagnosis confirmation is gained by pathologic and/or genetic testing or by observing the natural course of the disease. Family history and examination of affected family members can be helpful. Consulting a geneticist is recommended for counseling.

Who is at Risk for Developing this Disease?

PPKs are primarily genetic and/or hereditary. The mode of inheritance can be autosomal recessive, autosomal dominant, x-linked, a combination of all three, or acquired. The mode of inheritance for all of the PPK syndromes can be found in the “notes” section on the included table.

What is the Cause of the Disease?

The cause for a PPK is highly variable. The genetic basis for many of these disorders is known. Genetic testing for those will identify a pathogenic gene defect. Please refer to the “Genetic Cause/Association” column for gene defect information for each syndrome.

Systemic Implications and Complications

Several PPKs are associated with severe systemic problems such as gastrointestinal, neurological, or cardiac involvement. Disorders with severe systemic implications whould be ruled out first. There are a few syndromes to be highlighted due to the high occurrence of associated cancer:

Howel-Evans is characterized by the onset of esophageal carcinoma. Until esophageal carcinoma develops, it is difficult to accurately diagnose this syndrome (See Figure 34, Figure 35).

Treatment should be tailored to the patient’s individual symptoms. The above treatments have been listed as successsful in certain cases. The patient should be seen in follow up as needed to ease the symptoms.

Optimal Therapeutic Approach for this Disease

It is very rare for an optimal therapeutic approach to exist for these disorders. Evidence from trials is lacking for the established treatments. Most patients require symptomatic relief as discussed in “Treatment options” above.

Treatment (cure) of the tumor/cancer in Howell Evans syndrome does not result in resolution of the PPK.

Patient Management

As noted in the “Additional Specialists Needed” column on the attached table, a helpful patient management tactic for PPKs is to be familiar with the systemic implications associated with PPKs. This will enable a physician to refer his or her patients to the correct specialist.

Unusual Clinical Scenarios to Consider in Patient Management

Manifestations of each PPK may altered by an underlying inflammatory infection, fungal, or bacterial component. Also, be aware of the possibility that a clincal presentation might be a combination of one or more individual disorders.

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